Barcode Knight Channels The Old Thrill of Monster Hunter
One of my personal favorite games growing up was Monster Rancher, mostly because I could use one of the dozens of CDs my dad had laying around the house to summon different monsters to see what I could come up with. Barcode Knight is a lot like that, except you scan UPC codes to fight in different dungeons generated from the codes you find. The thrill is generating different dungeons with special monsters here and there, and leveling up your character the best you can.
You'll also pick up new pieces of equipment, earn gold, and then hit up new dungeons according to the codes you scan in. There's plenty of UPCs to scan in, too. Just look around your house at any given time, especially what's in the kitchen. Plenty to be found there. Or even books and CDs -- you'd be surprised at what you can scan in. It'll give trips to the store a brand new dimension of fun as well.